Lib.Audio3d: sceAudio3dGetDefaultOpenParameters fix (#3923)

* OrbisAudio3dOpenParameters struct fix

Not sure why we have the extra filler, but decomp suggests it shouldn't exist.
This fixes stack_chk_fail issues in audio3d using titles.

* Bring back filler, only copy 0x20 bytes.

The library accepts variations on struct size, with the maximum size being the 0x28 size our current struct has.
This fixes the issue without potentially breaking the struct.

* Fix memcpy

Prevent OOB read